Friction device for winding machines



June 6, 1967 w. 1. SCHMIDT 3,323,747

FRICTION DEVICE FOR WINDING MACHINES j Filed May 5, 1965 INVENTOR.

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United States Patent O FRICTION DEVICE ORWINDING MACHINES Willi J. Schmidt, Kelkheim, Taunus, Germany, assignor to Kalle Aktiengesellschaft, Wiesbaden-Biebrich, Germany Filed May 3, 1965, Ser. No. 452,472

Claims priority, application Germany, May 6, 1964,

7 ciaims.(c1. 242-7s.4)

The present invention relates to a friction device for winding machines which ensures, during the winding-up operation, a predetermined tension of a web to be wound up. This friction device is used when plural windings, e.g. of narrow webs of films which are produced by longitudinally dividing a wide web of film, are to be performed on a common winding shaft, which, due to the differences of the thickness of the initial web often occurring, would not result in accurate conveyance. Exact winding further requires smooth running of the winding core and of the units supporting the winding core on the winding shaft.

Known friction devices generally have the following construction: Between two discs mounted on the winding shaft, which are movable along the winding shaft but secured against any torsion, there are two additional discs supporting the winding core and rotating on the winding shaft. Between an outer mounted disc and an inner rotating disc there are discs of felt or synthetic plastic, which, by means of an adjusting ring of variable pressure, may contact the rotating center discs, the outer mounted discs serving as abutments. Corresponding to the contact .pressure of the felt or plastic discs on the center discs supporting the winding core, a predetermined torsional moment is transferred by the leading winding shaft to the rotating discs and thus to the winding core, this causing a certain tension of the web to be wound up.

The known friction devices have the advantage of being simple, but also exhibit a variety of drawbacks. Particularly, there is insufficiently accurate conveyance in the known devices, especially as regards soft friction. Lateral conveyance of the wound-up web results in a considerable percentage of scrap. Although the adjusting ring makes possible a gradual variable tenison of the web, it is almost impossible, for various reasons, to maintain this tension during a longer period. The lateral limitation by the mounted adjusting rings, for example, may cause a linear expansion of the side discs by means of frictional heat, which results in an increase of the contact pressure of the felt discs and thus in an undesirable increase of the web tension. It has been attempted, by incorporating springs between the adjusting ring and the friction discs, to prevent this kind of tightening but tests showed that the winding `cores are then even more likely to swing and sideslip. Furthermore, the application of felt discs involves a certain abrasion which causes contamination of the lm Webs to be wound up. The requirement of disassembling the entire friction unit when removing a wound reel involves another drawback in that it is extremely difficult Lto adjust exactly the same tension for the next succeeding winding operation.

The present invention provides a friction device which overcomes the drawbacks mentioned above and ensures smooth and exact winding.

The invention will be further illustrated by reference to the accompanying drawings in which:

FIGURE l is a view in longitudinal section through one embodiment of a friction device according to the present invention, and

FIGURE 2 is a sectional view taken on line 2 2 of FIGURE 1.

The friction device of the present invention comprises two concentrically mounted rings 1 and 2 which are ro- Patented June 6, 1967 ICC tatable with respect to each other with gradually variable friction and without lateral movement in a plane at a right angle to the common axis and in the common center, the friction between the inner ring 1 and the outer ring 2 being effected by brake devices 8 and 8 in the annular space 12 between the outer ring 2 .and the inner ring 1. An adjusting ring 10 is mounted on the inner ring 1 and at least partially covers the annular space. The brake devices are interconnected on one side by a resilient means 14 and, on the other side, one of them is mounted by the bolt 13 on t-he inner ring 1 and one is mounted by the bolt 13' on the adjusting ring 10 which is adjustable, in various positions in the zone of the slots 17 by means of fastening devices, with respect to the inner ring 1.

Exact running of the two concentric rings 1 and 2 of the friction device of the present invention may be effected by a radially and axially supporting bearing between the inner ring 1 and the outer ring 2, e.g. a ball bearing, which can be adjusted so as to operate smoothly and with freedom from play.

The brake devices 8 and 8 may comprise friction material generally used for brake linings. Their number need not be two, as shown in FIGURE 2, and more than two brake devices may be mounted in the space 12. The resilient means 14, the deformation of which is adjustable by means of the adjusting ring 10 and which regulates the contact pressure of the brake devices 8 on the inner surface of .the outer ring 2, preferably is a steel compression spring. Other elastic materials, such as rubber, also may be used for this purpose.

The inner ring 1 has means on its inner surface whereby the friction device can be mounted on a winding shaft. The device preferably comprises a key 18 radially mounted on the inside and adapted to engage in a groove of the winding shaft.

On the outer ring 2, the friction device of the present invention has means capable -of coupling the outer ring 2 and the winding core 9. A clamping device preferably is used for this purpose, which comprises the groove 4a,-

limited on one side by the outer ring 2 and on the other side by the threaded ring 3 rotating on the outer ring 2 between two stops, and the spiral spring 4 in thel groove 4a. The vertical side walls of the groove 4a are provided with sloped `sections projecting against the spiral spring 4, the sloped sections being adjustable by rotating the threaded ring 3 so that they are opposite to each other, to increase tension, or alternating, to release tension. When the sloped sections of the `threaded ring 3 and the outer ring 2 are opposed, the spiral spring 4 is raised from the groove 4a and against the winding core. If, however, a vertical section of the flank of the outer ring 2 is opposite to a sloped projection of the .threaded ring 3, the tension spring 4 seats in the groove 4a and the winding core 9 is released.

The outer periphery of the outer ring 2 is further provided with a plurality of small projections 16 serving as lateral stops for the winding core 9. The winding core 9 correspondingly possesses on its periphery, over the entire width, an equal number of depressions which are spaced in such a manner that, in a matching position, the winding core 9 can be drawn over the projections of the outer ring 2. The advantage of this arrangement lies in .the fact that, when removing the winding cores upon completion of the winding operation, it is not necessary to remove the entire friction devices, but the individual winding cores, the spring 4 being released, can be passed over any number of friction devices to the end of the winding shaft, where they can be taken off by removing this end from the bearing. A new adjustment of the web tension is thus not required for the next succeeding winding operation.

A preferred embodiment of the friction device of the present invention is illustrated in the attached drawing.

In FIGURE 1 there are shown two concentrically mounted rings 1 and 2, the inner ring having a key 18 by means of which it can be keyed in the keyway of a winding shaft. The outer ring 2 is coupled with the winding core 9 by means of a clamping device. Grooves on the inner ring 1 and on the outer ring 2, whichare opposite to each other and preferably are of a square cross-section, form a bearing .race for the smoothly running, radially and axially supporting ball bearings 5 which, by means of the adjusting ring 6 and retaining plate 7, can be adjusted to be free from play. In the annular space 12, which is sealed by a labyrinth seal, there are two radially operating brake shoes 8 and 8 connected by the compression spring y 14. One of the shoes is mounted by the bolt 13 on the inner ring 1 and the other by the bolt 13' on the adjusting ring 10. The brake shoes 8, which serve to obtain a desired friction value depending on the winding width and winding material, are on the outside adjacent to an extension of the outer ring 2, which simultaneously is the outer part of the ball bearing race. The adjustment of the contact pressure of the brake shoes 8 and 8 on the outer ring 2, and thus the regulation of the friction value, is performed by turning the adjusting ring 10, which is mounted on the inner ring 1, after loosening the two screws 11 and 11 which then can be moved in the slots 17.

Adjustment of the adjusting ring 10 is limited by the end walls 15, at the ends of the slots 17, by means of which the adjusting ring 10 is secured to the inner ring 1. The height of the end walls .15 determines the width of the annular space 12. The bolt 13 serves as a fixed point of the brake shoe 8 and is mounted on the adjusting ring 10, whereas the bolt 13', secured to the brake shoe 8,', is connected with the inner ring 1. After loosening the screws 11 and 11', the adjusting ring 10 can be moved to another position, the bolts 13 and 13 being separated from each other or moved towards each other, in accordance with the direction of rotation. On the opposite side of the annular space 12 at the other end of the brake shoes 8 .and 8', this movement becomes inversely effective as longitudinal change of the compression spring 14, which presses the brake shoes 8 and 8 more or less against the braking area of the outer ring 2.

The outer periphery of the outer ring 2 is provided with a clamping device which comprises the threaded ring 3 and the spiral tension spring 4. As shown in .FIGURE 1, the plane side of the threaded ring 3 which is opposite to the spiral tension spring 4 is intermittently provided with conical projections which project from the rectangular plane side of the threaded ring 3. 4In a corresponding manner, the opposite ila-nk of the outer ring 2 is intermittently conically formed so that, when the corresponding conical sections are opposite to each other, the tension spring 4 passing around the entire periphery is forced out of the groove 4a by means of this enlargement of the diameter in the zones of the conical sections and thus clamps the winding core 9.

IFurthermore, there are several narrow, projections 16 mounted on the outer periphery of the outer ring 2, for example spaced by 90, which serve as abutments for the winding core 9.

The friction device of the present invention has the following advantages over the prior art:

(1) The radially and axially supporting, smoothly running ball bearing ensures accurate conveyance, which has not been obtained before.

(2) The winding torsion, once adjusted, remains constant during the entire winding operation and, in the case of performing a series of successive winding operations, need not be readjusted.

(3) The friction device need not be removed when removing the winding core.

(4) The clamping device ensures rapid and smooth mounting of the winding cores.

(5) The compact construction of the entire friction device permits a substantially simpler handling than is the case with prior art friction devices.

Using the new friction device, exact windings may be obtained by simpler and more rapid handling andv with very little waste.

It will be obvious to those skilled in the art that many modifications may be made within the scope ofthe present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. A friction device for a winding machine which cornprises two relatively rotatable, concentric, inner and outer rings having an annular space between them, an adjusting ring mounted on the inner ring, and a pair of brake shoes in the annular space, one being pivotally secured at one end thereof to the inner ring and one being pivotally secured at one end thereof to the adjusting ring, the other ends of the brake shoes being connected by spreading mea-ns.

2. A friction device according to claim 1 including bearing means between the inner and outer rings.

3. A friction device according to claim 1 including means for locking the adjusting ring in a desired position.

4. A friction device according to claim 1 in which the spreading means is a compression spring.

5. A friction device according to claim 1 including clamping means on the outer ring whereby the latter can be connected to a winding core.

6. A friction device according to claim 5 in which the clamping means comprises a groove in the periphery of the outer ring, a spring in the groove, and means for raising the spring in the groove over at least a portion of the periphery of the outer ring.

7. A friction device according to claim 1 in which the periphery of the outer ring has a plurality of projections thereon which serve as abutments for a winding core.

References Cited UNITED STATES PATENTS 2,206,3 8l 7/1940 Zimmerman 242-75 2,405,446 8/ 1946 Perrault 242-75 X 2,726,051 12/ 195 5 Deichert 242-5 6 FRANK I. COHEN, Primary Examiner.

N'. L. MINTZ, Assistant Examiner. 

1. A FRICTION DEVICE FOR A WINDING MACHINE WHICH COMPRISES TWO RELATIVELY ROTATABLE, CONCENTRIC, INNER AND OUTER RINGS HAVING AN ANNULAR SPACE BETWEEN THEM, AN ADJUSTING RING MOUNTED ON THE INNER RING, AND A PAIR OF BRAKE SHOES IN THE ANNULAR SPACE, ONE BEING PIVOTALLY SECURED AT ONE END THEREOF TO THE INNER RING AND ONE BEING PIVOTALLY SECURED AT ONE END THEREOF TO THE ADJUSTING RING, THE OTHER ENDS OF THE BRADE SHOES BEING CONNECTED BY SPREADING MEANS. 